skyjack vs pirate

skyjack is not a noun while pirate is a noun.

Word	Noun	Adjective	Verb	Adverb
skyjack	No	No	Yes	No
pirate	Yes	No	Yes	No

As verbs, pirate is a hypernym of skyjack; that is, pirate is a word with a broader meaning than skyjack:

Other hypernyms of skyjack include commandeer, highjack, hijack.

skyjack (noun)	pirate (noun)
	a ship that is manned by pirates
	someone who robs at sea or plunders the land from the sea without having a commission from any sovereign nation
	someone who uses another person's words or ideas as if they were his own

skyjack (verb)	pirate (verb)
subject an aircraft to air piracy	take arbitrarily or by force
	copy illegally; of published material